On 'Black Tuesday,' October 29, 1929, the Wall Street stock market crashed, signaling the beginning of the Great Depression. The crash followed a decade of unchecked speculation and the 'Roaring Twenties,' where millions of people invested their savings or borrowed money to buy stocks, pushing prices to unsustainable levels. When the bubble burst, billions of dollars were wiped out, leading to thousands of bank failures and the evaporation of personal savings. Unemployment in the U.S. eventually reached 25%, and global trade plummeted by more than 50%. The event led to a radical shift in the role of the U.S. government, as President Franklin D. Roosevelt introduced the 'New Deal,' a series of programs to provide relief, recovery, and reform. The depression lasted until the massive industrial mobilization of World War II, fundamentally changing how governments manage their economies.